The present invention relates to a burner for a Stirling engine, and more particularly to a burner for improving heat transfer to a heater tube and preventing corrosion of the heater tube.
Generally, a conventional burner for a Stirling engine includes a combustion chamber 6 forming a an air-fuel mixture by mixing air and fuel supplied from air inlet passageways 2 and a fuel injection nozzle 4, an igniter 10 producing a flame 8 by igniting the air-fuel mixture formed within the combustion chamber 6, heater tube 16 absorbing high temperature heat generated by the combustion of the air-fuel mixture and transferring it to a Stirling engine 12, and exhaust gas passageways 14 discharging an exhaust gas to the outside.
That is, the fuel injected from the fuel injection nozzle 4, mixes with the air supplied from the air inlet passageways 2, resulting in the air-fuel mixture within the combustion chamber 6. This mixture is ignited by the igniter 10 provided at the combustion chamber 6, and thus the flame 8 is produced. At this time, the high temperature combustion gas generated by the combustion of the air-fuel mixture, transfers the heat through the heater tube 16 of the Stirling engine 12 to the inside of the Stirling engine 12, and then is discharged to the outside through the exhaust gas passageways 14.
Since the air inlet passageways 2 and the exhaust gas passageways 14 are separated by a wall formed between them, the air supplied from the air inlet passageways 2 is preheated by the heat of the exhaust gas because of the heat transfer through the wall.
Since the usual temperature of the flame 8 is above 1000.degree. C., if the flame 8 comes into direct contact with the heater tube 16, it can cause the heater tube 16 to melt. In addition, because high pressure is maintained and pulsating pressure exists in the operation of the Stirling engine 12, the heater tube 16 are apt to corrode by creeping according to an internal pressure, thermal stress resulting from the temperature, or the exhaust gas.
In order to suppress the above-mentioned phenomena in the conventional burner, the height L of the combustion chamber 6 is heightened and thus it is possible to prevent the flame 8 from coming into direct contact with the heater tube 16. As a result, however, the Stirling engine system increases in total size. In addition, since the distance between the heater tube 16 and the flame 8 becomes more distant as a result of this, it is difficult to discharge the exhaust gas throughout the heater tube 16 and the amount of the heat radiated from the flame 8 to the heater tube 16 is reduced, so that the efficiency of the Stirling engine 12 also decreases. At this time, if the heater tube 16 is made of corrosion-resistant super alloy such as hastelloy and inconel, manufacturing cost increases.